Figure 2.

TEM and HRTEM images and sketch map of the structure of one ZnO nanoflower. (a) TEM image of one ZnO nanoflower; (b) HRTEM image of the region in the stalk, which is marked by a small square in (a); (c) the enlarged image corresponding to the region marked by the big square in (a); (d) a sketch map of the nanoflower structure.